The invention relates to a coupling device with electrical isolation comprising:                at least one input of an input signal,        an output of an output signal representative of said input signal, and        signal transfer means with electrical isolation receiving the input signal and supplying said output signal,        at least one signal transformer (14) having at least one primary winding to receive a primary signal representative of said input signal,        switching means to switch the input signal and provide said primary signal representative of said input signal to said primary winding,        control means of the switching means comprising a control signal input receiving control signals during switching periods, and an output electrically isolated from the control signal input and connected to said switching means to command primary signal switching during said switching periods.        
The invention also relates to an electrical equipment unit comprising one such coupling device.